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| /**
* Copyright 2017 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { CredentialsProvider } from '../api/credentials';
import { User } from '../auth/user';
import {
EventManager,
ListenOptions,
Observer,
QueryListener
} from './event_manager';
import { SyncEngine } from './sync_engine';
import { EagerGarbageCollector } from '../local/eager_garbage_collector';
import { GarbageCollector } from '../local/garbage_collector';
import { IndexedDbPersistence } from '../local/indexeddb_persistence';
import { LocalStore } from '../local/local_store';
import { MemoryPersistence } from '../local/memory_persistence';
import { NoOpGarbageCollector } from '../local/no_op_garbage_collector';
import { Persistence } from '../local/persistence';
import { Mutation } from '../model/mutation';
import { Platform } from '../platform/platform';
import { Datastore } from '../remote/datastore';
import { RemoteStore } from '../remote/remote_store';
import { JsonProtoSerializer } from '../remote/serializer';
import { AsyncQueue } from '../util/async_queue';
import { Code, FirestoreError } from '../util/error';
import { debug } from '../util/log';
import { Deferred } from '../util/promise';
import { DatabaseId, DatabaseInfo } from './database_info';
import { Query } from './query';
import { Transaction } from './transaction';
import { OnlineState } from './types';
import { ViewSnapshot } from './view_snapshot';
const LOG_TAG = 'FirestoreClient';
/**
* FirestoreClient is a top-level class that constructs and owns all of the
* pieces of the client SDK architecture. It is responsible for creating the
* async queue that is shared by all of the other components in the system.
*/
export class FirestoreClient {
// NOTE: These should technically have '|undefined' in the types, since
// they're initialized asynchronously rather than in the constructor, but
// given that all work is done on the async queue and we assert that
// initialization completes before any other work is queued, we're cheating
// with the types rather than littering the code with '!' or unnecessary
// undefined checks.
private eventMgr: EventManager;
private garbageCollector: GarbageCollector;
private persistence: Persistence;
private localStore: LocalStore;
private remoteStore: RemoteStore;
private syncEngine: SyncEngine;
constructor(
private platform: Platform,
private databaseInfo: DatabaseInfo,
private credentials: CredentialsProvider,
/**
* Asynchronous queue responsible for all of our internal processing. When
* we get incoming work from the user (via public API) or the network
* (incoming GRPC messages), we should always schedule onto this queue.
* This ensures all of our work is properly serialized (e.g. we don't
* start processing a new operation while the previous one is waiting for
* an async I/O to complete).
*/
private asyncQueue: AsyncQueue
) {}
/**
* Starts up the FirestoreClient, returning only whether or not enabling
* persistence succeeded.
*
* The intent here is to "do the right thing" as far as users are concerned.
* Namely, in cases where offline persistence is requested and possible,
* enable it, but otherwise fall back to persistence disabled. For the most
* part we expect this to succeed one way or the other so we don't expect our
* users to actually wait on the firestore.enablePersistence Promise since
* they generally won't care.
*
* Of course some users actually do care about whether or not persistence
* was successfully enabled, so the Promise returned from this method
* indicates this outcome.
*
* This presents a problem though: even before enablePersistence resolves or
* rejects, users may have made calls to e.g. firestore.collection() which
* means that the FirestoreClient in there will be available and will be
* enqueuing actions on the async queue.
*
* Meanwhile any failure of an operation on the async queue causes it to
* panic and reject any further work, on the premise that unhandled errors
* are fatal.
*
* Consequently the fallback is handled internally here in start, and if the
* fallback succeeds we signal success to the async queue even though the
* start() itself signals failure.
*
* @param usePersistence Whether or not to attempt to enable persistence.
* @returns A deferred result indicating the user-visible result of enabling
* offline persistence. This method will reject this if IndexedDB fails to
* start for any reason. If usePersistence is false this is
* unconditionally resolved.
*/
start(usePersistence: boolean): Promise<void> {
// We defer our initialization until we get the current user from
// setUserChangeListener(). We block the async queue until we got the
// initial user and the initialization is completed. This will prevent
// any scheduled work from happening before initialization is completed.
//
// If initializationDone resolved then the FirestoreClient is in a usable
// state.
const initializationDone = new Deferred<void>();
// If usePersistence is true, certain classes of errors while starting are
// recoverable but only by falling back to persistence disabled.
//
// If there's an error in the first case but not in recovery we cannot
// reject the promise blocking the async queue because this will cause the
// async queue to panic.
const persistenceResult = new Deferred<void>();
let initialized = false;
this.credentials.setUserChangeListener(user => {
Eif (!initialized) {
initialized = true;
this.initializePersistence(usePersistence, persistenceResult)
.then(() => this.initializeRest(user))
.then(initializationDone.resolve, initializationDone.reject);
} else {
this.asyncQueue.enqueue(() => {
return this.handleUserChange(user);
});
}
});
// Block the async queue until initialization is done
this.asyncQueue.enqueue(() => {
return initializationDone.promise;
});
// Return only the result of enabling persistence. Note that this does not
// need to await the completion of initializationDone because the result of
// this method should not reflect any other kind of failure to start.
return persistenceResult.promise;
}
/** Enables the network connection and requeues all pending operations. */
enableNetwork(): Promise<void> {
return this.asyncQueue.enqueue(() => {
return this.remoteStore.enableNetwork();
});
}
/**
* Initializes persistent storage, attempting to use IndexedDB if
* usePersistence is true or memory-only if false.
*
* If IndexedDB fails because it's already open in another tab or because the
* platform can't possibly support our implementation then this method rejects
* the persistenceResult and falls back on memory-only persistence.
*
* @param usePersistence indicates whether or not to use offline persistence
* @param persistenceResult A deferred result indicating the user-visible
* result of enabling offline persistence. This method will reject this if
* IndexedDB fails to start for any reason. If usePersistence is false
* this is unconditionally resolved.
* @returns a Promise indicating whether or not initialization should
* continue, i.e. that one of the persistence implementations actually
* succeeded.
*/
private initializePersistence(
usePersistence: boolean,
persistenceResult: Deferred<void>
): Promise<void> {
if (usePersistence) {
return this.startIndexedDbPersistence()
.then(persistenceResult.resolve)
.catch((error: FirestoreError) => {
// Regardless of whether or not the retry succeeds, from an user
// perspective, offline persistence has failed.
persistenceResult.reject(error);
// An unknown failure on the first stage shuts everything down.
if (!this.canFallback(error)) {
return Promise.reject(error);
}
console.warn(
'Error enabling offline storage. Falling back to' +
' storage disabled: ' +
error
);
return this.startMemoryPersistence();
});
} else {
// When usePersistence == false, enabling offline persistence is defined
// to unconditionally succeed. This allows start() to have the same
// signature for both cases, despite the fact that the returned promise
// is only used in the enablePersistence call.
persistenceResult.resolve();
return this.startMemoryPersistence();
}
}
private canFallback(error: FirestoreError): boolean {
return (
error.code === Code.FAILED_PRECONDITION ||
error.code === Code.UNIMPLEMENTED
);
}
/**
* Starts IndexedDB-based persistence.
*
* @returns A promise indicating success or failure.
*/
private startIndexedDbPersistence(): Promise<void> {
// TODO(http://b/33384523): For now we just disable garbage collection
// when persistence is enabled.
this.garbageCollector = new NoOpGarbageCollector();
const storagePrefix = IndexedDbPersistence.buildStoragePrefix(
this.databaseInfo
);
// Opt to use proto3 JSON in case the platform doesn't support Uint8Array.
const serializer = new JsonProtoSerializer(this.databaseInfo.databaseId, {
useProto3Json: true
});
this.persistence = new IndexedDbPersistence(storagePrefix, serializer);
return this.persistence.start();
}
/**
* Starts Memory-backed persistence. In practice this cannot fail.
*
* @returns A promise that will successfully resolve.
*/
private startMemoryPersistence(): Promise<void> {
this.garbageCollector = new EagerGarbageCollector();
this.persistence = new MemoryPersistence();
return this.persistence.start();
}
/**
* Initializes the rest of the FirestoreClient, assuming the initial user
* has been obtained from the credential provider and some persistence
* implementation is available in this.persistence.
*/
private initializeRest(user: User): Promise<void> {
return this.platform
.loadConnection(this.databaseInfo)
.then(connection => {
this.localStore = new LocalStore(
this.persistence,
user,
this.garbageCollector
);
const serializer = this.platform.newSerializer(
this.databaseInfo.databaseId
);
const datastore = new Datastore(
this.asyncQueue,
connection,
this.credentials,
serializer
);
const onlineStateChangedHandler = (onlineState: OnlineState) => {
this.syncEngine.applyOnlineStateChange(onlineState);
this.eventMgr.applyOnlineStateChange(onlineState);
};
this.remoteStore = new RemoteStore(
this.localStore,
datastore,
this.asyncQueue,
onlineStateChangedHandler
);
this.syncEngine = new SyncEngine(
this.localStore,
this.remoteStore,
user
);
// Setup wiring between sync engine and remote store
this.remoteStore.syncEngine = this.syncEngine;
this.eventMgr = new EventManager(this.syncEngine);
// NOTE: RemoteStore depends on LocalStore (for persisting stream
// tokens, refilling mutation queue, etc.) so must be started after
// LocalStore.
return this.localStore.start();
})
.then(() => {
return this.remoteStore.start();
});
}
private handleUserChange(user: User): Promise<void> {
this.asyncQueue.verifyOperationInProgress();
debug(LOG_TAG, 'User Changed: ' + user.uid);
return this.syncEngine.handleUserChange(user);
}
/** Disables the network connection. Pending operations will not complete. */
disableNetwork(): Promise<void> {
return this.asyncQueue.enqueue(() => {
return this.remoteStore.disableNetwork();
});
}
shutdown(): Promise<void> {
return this.asyncQueue
.enqueue(() => {
this.credentials.removeUserChangeListener();
return this.remoteStore.shutdown();
})
.then(() => {
// PORTING NOTE: LocalStore does not need an explicit shutdown on web.
return this.persistence.shutdown();
});
}
listen(
query: Query,
observer: Observer<ViewSnapshot>,
options: ListenOptions
): QueryListener {
const listener = new QueryListener(query, observer, options);
this.asyncQueue.enqueue(() => {
return this.eventMgr.listen(listener);
});
return listener;
}
unlisten(listener: QueryListener): void {
this.asyncQueue.enqueue(() => {
return this.eventMgr.unlisten(listener);
});
}
write(mutations: Mutation[]): Promise<void> {
const deferred = new Deferred<void>();
this.asyncQueue.enqueue(() => this.syncEngine.write(mutations, deferred));
return deferred.promise;
}
databaseId(): DatabaseId {
return this.databaseInfo.databaseId;
}
transaction<T>(
updateFunction: (transaction: Transaction) => Promise<T>
): Promise<T> {
// We have to wait for the async queue to be sure syncEngine is initialized.
return this.asyncQueue
.enqueue(async () => {})
.then(() => this.syncEngine.runTransaction(updateFunction));
}
}
|